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Discussion Starter · #1 ·
Hi all,

So, the long story short is this: I have a salvage yard engine installed in my 1996 626 4cyl. The yard engine had 76K original miles, but has sat unused on their shelf for roughly 15 years or so without running or being turned over. It smokes like a mosquito fogger (bluish-grey smoke, oil burn) on start-up, especially when cold. It does not seem to burn any once it reaches normal operating temperature. I have ran this engine hard, and put a couple thousand miles on it so far (road trip to North Carolina and back.) It did not burn much at all when running at temperature over those miles to NC and back, just on cold start.

I pulled the head and had it machined, clean deck with new valve seats / seals / guides, which drastically increased performance of the 'yard engine. It runs and drives almost like new, except for this oil burn issue.

In the garage, I have the original engine which did not have this oil burn problem, but the head is garbage. So I could theoretically pull the yard engine back out, swap the head over to the original engine, and put it back in - but - before I do that, I have some questions for you all:
  1. Do you agree from the symptoms, that this is likely broken or stuck (in the groove) piston rings?
  2. If so, would you try any magic solvents to free them? (such as 24-48hr soaking with Kroil or something similar)
  3. If not, what do you think is the likely cause?
  4. ...Other ideas or suggestions?
Thanks in advance! I guess I'm hoping there's a way to reduce or resolve the oil burn without once again pulling out the cherry picker and, let's be honest, I don't know how much more of a beating those CV axle C-clips can take when pulling this sucker. Barely managed to get them back in last time...

-Jim
 

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Its been a while since I have worked on an engine that old. Does it have a diagnostic port that you could plug into to get some computer readings on the engine? Maybe it is just running really rich and needs a good tune?
 

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Discussion Starter · #3 ·
Its been a while since I have worked on an engine that old. Does it have a diagnostic port that you could plug into to get some computer readings on the engine? Maybe it is just running really rich and needs a good tune?
Thanks for the reply, yes it does have OBD2. I looked over o2 readings, they seem within normal range, and the MAF / TPS readings also seem normal. I thought rich-running would produce black, not grey smoke? Maybe I'm mistaken.
Anyway, it's a good thought to be doubly-sure it's not related to bad sensors / control systems. This engine is old enough to still be mechanically timed, and I was certain to make sure the reading is 12 BTDC (manual trans)
 
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